J/A+A/628/A81 Gaia DR2-based catalogue of 237 Ap stars (Scholz+, 2019)
Strongly magnetic Ap stars in the Gaia DR2 Hertzsprung-Russell diagram.
I. Selecting the most reliable astrometric and photometric data.
Scholz R.-D., Chojnowski, S.D., Hubrig S.
<Astron. Astrophys. 628, A81 (2019)>
=2019A&A...628A..81S 2019A&A...628A..81S (SIMBAD/NED BibCode)
ADC_Keywords: Stars, Ap ; Parallaxes, trigonometric ; Proper motions ;
Photometry, UBVRI ; Effective temperatures
Keywords: catalogues - binaries: general - stars: distances -
Hertzsprung-Russell and C-M diagrams - stars: magnetic field -
stars: variables: general
Abstract:
Knowing the distribution of strongly magnetic Ap stars in the
Hertzsprung-Russell diagram (HRD) allows us to study the evolution of
their magnetic fields across the main sequence (MS). With a newly
extended Ap star sample from APOGEE and available Gaia DR2 data, we
can now critically review the results of previous studies based on
Hipparcos data. To investigate our targets in the Gaia DR2 HRD, we
need to define astrometric and photometric quality criteria to remove
unreliable data from the HRD. We used the Gaia DR2 renormalised unit
weight error RUWE as our main quality criterion. We considered known
(close) binaries in our sample compared to their (partly affected)
astrometry and used the Gaia DR2 data to find common parallax and
proper motion (CPPM) wide companions and open cluster members. We
studied G, BP and RP variability amplitudes and their significance as
a function of magnitude. In colour-magnitude diagrams (CMDs) with
absolute G magnitude (determined from inverted parallax) versus BP-RP
colour and HRDs, where BP-RP is replaced by effective temperature, we
studied the appearance of outliers with respect to their astrometric
quality, binarity, and variability. We present a catalogue of 83
previously known and 154 new strongly magnetic Ap stars with Gaia DR2
data, including astrometric quality parameters, binary flags,
information on cluster membership, variability amplitudes, and data
from Hipparcos. Our astrometrically cleaned subsamples include 47 and
46 old and new Ap stars with parallaxes >2mas. Most of the known 26
binaries among all 237 stars and 14 out of 15 CMD/HRD outliers were
excluded by astrometric criteria. The remaining 11 known binaries and
a few highly variable objects mainly appear in the bright and red
CMD/HRD parts. A CMD based on Hipparcos photometry and Gaia DR2
parallaxes shows a much more narrow distribution in the absolute V
magnitudes of 75 common Ap stars over the full B-V colour range than
the corresponding CMD based on Hipparcos parallaxes.
Description:
Except for the main astrometric data from Gaia DR2 we include in our
catalogue of 237 strongly magnetic Ap stars astrometric quality
criteria that were not given in the original Gaia DR2, information on
the existence of close and wide binary companions and open cluster
membership, and additional parameters related to photometric quality
and possible variability of these objects. The astrometrically most
reliable and non-variable stars as well as known close binaries in the
catalogue are flagged. For 75 stars already measured by Hipparcos, we
provide Hipparcos astrometry, including parameters describing the
quality of the data, and photometry. Except for three objects,
2MASS J17380465-2146101, 2MASS J17534913-3332308, and
2MASS J18151324+0121014, the names listed in the catalogue are all
resolved by SIMBAD.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 338 237 Gaia DR2-based Catalogue of magnetic Ap stars
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See also:
I/311 : Hipparcos, the New Reduction (van Leeuwen, 2007)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/601/A14 : Radial velocities of magnetic Ap stars (Mathys, 2017)
Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 24 A24 --- Name (SIMBAD) name of Ap star, typically HD ...
or 2MASS ... (1)
26- 53 A28 --- GaiaDR2 Unique Gaia source designation (3)
55- 64 F10.4 mas Plx ? Gaia DR2 parallax (3)
67- 72 F6.4 mas e_Plx ? error of Gaia DR2 parallax (3)
74- 83 F10.4 --- RPlx ? Gaia DR2 parallax divided by its error (3)
85- 93 F9.3 mas/yr pmRA ? Gaia DR2 proper motion component in right
ascension direction pmRA*cos(DE) (3)
96-100 F5.3 mas/yr e_pmRA ? error of pmRA (3)
102-110 F9.3 mas/yr pmDE ? Gaia DR2 proper motion component in
declination direction (3)
113-117 F5.3 mas/yr e_pmDE ? error of pmDE (3)
119-120 I2 --- Np Gaia DR2 Nper = visibility_periods_used (3)
122-128 F7.4 mag Gmag Gaia DR2 G magnitude (3)
130-136 F7.4 mag BPmag Gaia DR2 BP magnitude (3)
138-144 F7.4 mag BP-RP Gaia DR2 BP-RP colour (3)
146-153 F8.4 --- u Gaia DR2 astrometric unit weight error
(3) (4) (11)
155-162 F8.3 --- RUWE Renormalised unit weight error (newly
calibrated u) (3) (5) (11) (4)
164-169 F6.4 --- vaG Variability amplitude in Gaia DR2
G band (3) (11) (6)
171-176 F6.4 --- vaB Variability amplitude in Gaia DR2
BP band (3) (11)
178-183 F6.4 --- vaR Variability amplitude in Gaia DR2
RP band (3) (11)
185-190 F6.2 --- vaGs Significance of vaG (number of standard
deviations sigma above the typical level
of non-variable stars) (3) (11)
192-197 F6.2 --- vaBs Significance of vaB (number of standard
deviations sigma above the typical level
of non-variable stars) (3) (11)
199-204 F6.2 --- vaRs Significance of vaR (number of standard
deviations sigma above the typical level
of non-variable stars) (3) (11)
206-212 F7.2 K Teff Stellar effective temperature (3) (8)
214-220 F7.2 K b_Teff Uncertainty (lower) on Teff estimate (3) (8)
222-228 F7.2 K B_Teff Uncertainty (upper) on Teff estimate (3) (8)
230-238 F9.3 Lsun Lum ? Estimated luminosity (3) (8)
240-246 F7.4 mag GMAG ? Absolute G magnitude computed as
MG=G+5log(Plx/100) (3) (11)
248-249 I2 --- wf Wide binary (common parallax and proper
motion = CPPM) flag (number of CPPM
companions) (3) (11)
251-252 I2 --- bf Close (with respect to Gaia measurements)
binary flag (0 = not known as binary) (1)
254-255 I2 --- cf Cluster membership flag (number of clusters
of which the star is a member) (3) (11) (9)
257-258 I2 --- af Astrometric quality flag (number of criteria
by which star was excluded, 0=best, 4=worst)
(11) (3) (5)
260-261 I2 --- vf Variability flag (number of photometric
bands, where the star lies >3sigma above the
typical variability amplitude) (3) (11)
263-268 I6 --- Hip ? Hipparcos identifier (10)
270 A1 --- N Note in first version of Hipparcos catalogue,
here: P = note on photometry (10)
274-275 I2 --- Sn ? Solution type new reduction,
5 = 5-parameter, 7 = 7-parameter solution,
>9 = double star with peculiarities (10)
277-278 I2 --- So ? Solution type old reduction,
0 = 5-parameter, 1 = 7- or 9-parameter,
3 = double/multiple stars,
4 = orbital binary (10)
280-281 I2 --- Nc ? Number of components according to
Hipparcos (10)
286-290 F5.2 mas HPlx ? Hipparcos parallax (new reduction) (10)
293-297 F5.2 mas e_HPlx ? Error of Hipparcos parallax (new reduction)
(10)
299-302 I4 --- Ntr ? Number of Hipparcos field transits
used (10)
304-309 F6.2 --- F2 ? Hipparcos goodness of fit (10)
311-313 I3 --- F1 ? Percentage of rejected Hipparcos
data (10)
316-322 F7.4 mag HPmag ? Hipparcos magnitude (in the optical V band
of the Hipparcos photometric system) (10)
324-330 F7.3 mag B-V ? Hipparcos B-V colour index (in the
non-conventional system) (10)
332-338 F7.3 mag V-I ? Hipparcos V-I colour index (no
standard system specified) (10)
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Note (1): data from Mathys (2017A&A...601A..14M 2017A&A...601A..14M, Cat. J/A+A/601/A14) and
as given by Chojnowski et al. (2019ApJ...873L...5C 2019ApJ...873L...5C)
Note (3): data taken from (or based on) Gaia Collaboration (2018A&A...616A...1G 2018A&A...616A...1G,
Cat. I/345)
Note (4): described by Lindegren et al. (2018A&A...616A...2L 2018A&A...616A...2L, Cat. I/345)
Note (5): described by Lindegren (GAIA-C3-TN-LU-LL-124-01)
Note (6): also described by Deason et al. (2017MNRAS.467.2636D 2017MNRAS.467.2636D) and
also described by Vioque et al. (2018A&A...620A.128V 2018A&A...620A.128V, Cat. IX/52)
Note (8): derived by Andrae et al. (2018A&A...616A...8A 2018A&A...616A...8A, Cat. I/345)
as part of Gaia DR2.
Note (9): based on cluster survey of Cantat Gaudin et al. (2018A&A...618A..93C 2018A&A...618A..93C,
Cat. J/A+A/618/A93)
Note (10): data taken from van Leeuwen (2007A&A...474..653V 2007A&A...474..653V, Cat. I/311)
Note (11): as derived in this paper
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Acknowledgements:
Ralf-Dieter Scholz, rdscholz(at)aip.de
(End) R.-D. Scholz [AIP, Potsdam, Germany], P. Vannier [CDS] 02-Aug-2019